Field of the Invention
Embodiments of the present disclosure relate to epoxy compositions and in particular to epoxy compositions that are combined with hardeners to form curable compositions. The curable compositions can be used to prepare prepregs.
Description of Background and Related Art
Epoxy thermosets have been used as the resin matrix to embed reinforced fibers to prepare lightweight and high strength composite articles for structural purposes. Among various composite manufacturing processes, the hot-melt prepreg process is a preferred process because it provides consistent properties and ease of use for composite fabricators, particularly in sporting goods, aerospace, automotive and other applications.
“Hot-melt” prepregs presented herein refer to fibers impregnated with solvent free, un-cured or slightly cured epoxy formulations. A typical manufacturing procedure involves (1) film manufacture and (2) film impregnation.
Many different types of high functional epoxy resins have been used to achieve high glass transition temperatures (Tg) of the cured epoxy thermosets to shorten de-molding time. However, the usage of these high functional epoxy resins may also cause a loss of adequate tackiness, and an increase in the melt viscosity of the resin blend, which can lead to insufficient resin wetting of the impregnated fibers, the formation of voids between the layered structures in composite articles, and a difficulty of preparing melt-epoxy-resin blends.
Therefore, a curable composition useful for preparing hot-melt prepregs which provides (1) adequate tack to serve as a semi-permanent adhesive (2) high glass transition temperature (Tg) and (3) an adequate viscosity profile for hotmelt prepreg processing is desired.